Kirk Wallace wrote: > Here is what I breadboarded that seems to work. > > http://www.wallacecompany.com/machine_shop/Shizuoka/watchdog-1b.png > > I used John's circuit and added the two inverters to the output because > the EMI from the mechanical relay engaging would cycle the solid-state > relay which would cycle the mechanical relay. Fortunately, it was a > degenerative oscillation. Adding the buffer to the output cleaned up the > problem. The component values are a combination of guessing, parts that > happen to be on the bench, and cut and try. I welcome any improvements > anyone might have. > > I loaded the charge-pump component to my .hal file and ran it in the > servo thread. Does the thread determine the pump frequency? I believe I > got 500 Hz out. > > I used these connections in the .hal file: > ... > # create a signal for the estop loopback > net estop-loop iocontrol.0.user-enable-out iocontrol.0.emc-enable-in > charge-pump.enable > net cp charge-pump.out parport.1.pin-04-out > ...
Using a schmidt trigger to clean up the output is good. However, there is one potential problem. The two stage charge pump can produce more than 5V, which the '14 might not like. Maybe a clamp diode to the supply rail? Or maybe use just one stage - remove C2, short D3. You'd have to make sure that one stage generates enough voltage to reliably trigger the '14. Regarding the frequency - yes, the period depends on the thread speed. It toggles the output each time it runs, so a 1KHz run rate = 500Hz out. Regards, John Kasunich ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
